One of the most striking epidemiological characteristics of prostatic cancer is the difference in occurrence between Blacks and Whites. This phenomenon has been apparent for all age groups since 1950. The reasons for this difference have not been demonstrated. We intend to test the hypothesis that the observed difference in prostatic cancer occurrence between Blacks and Whites is due to environmental factors, primarily socio-economic. The data will be obtained from the California Tumor Registry for Alameda County and the San Francisco Bay Area, the California death registry and from the U.S. Census. Multivariate statistical methods will be used for analysis. The objectives of this proposal are: 1. To add in a substantive way to the presently inconclusive evidence as to whether there is a relationship between prostatic cancer and economic status. 2. To determine to what extent the sizeable gap in prostatic cancer occurrence between Blacks and Whites in the U.S. is a function of environmental factors associated with economic status. 3. To test the often-made claim that members of the lower economic classes present with prostatic cancer at more advanced stages of the disease. 4. To observe time trends in prostatic cancer incidence by race and economic status.